1. Field of the Invention
The present invention relates to a manufacturing method of a liquid discharge head which discharges a desired liquid by using the production of bubbles caused by making thermal energy act on the liquid, a liquid discharge head, a head cartridge using the liquid discharge head, and a liquid discharge device.
Furthermore, the present invention is an invention which can be applied to a device such as a printer, a copying machine, a facsimile with a communication system, or a word processor with a printer portion, and further, an industrial recording apparatus compositely combined with various kinds of processors, which performs recording to a record medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics.
By the way, xe2x80x9crecordxe2x80x9d in the present invention means not only to give a meaningful image such as a character or a figure to a record medium but also to give a meaningless image such as a pattern.
2. Related Background Art
The ink jet recording method, the so-called bubble jet recording method has previously been known, in which a change of state accompanying a rapid change of volume (generation of bubbles) is caused in ink by giving energy of heat or the like to the ink, and the ink is discharged from an outlet by the acting force based on this change of state, and this is adhered onto a record medium, so that an image formation may be performed. A recording apparatus using this bubble jet recording method generally has an outlet for discharging ink, an ink flow passage connected to this outlet, and a heating element (electrothermal energy converting substance) which is arranged in the ink flow passage as an energy generating means for discharging the ink, as disclosed in Japanese Patent Publication No. 61-59911 and Japanese Patent Publication No. 61-59914.
By using the above recording method, an image with a high quality image can be recorded at a high speed and at a low noise level, and in the meantime, since outlets for discharging ink can be arranged with a high density, a head performing this recording method has a lot of advantages such as the advantage that a record image with a high resolution can easily be obtained, and further, a color image can also easily be obtained by a small sized device. Therefore, recently, this bubble jet recording method has been used in a lot of office machines such as a printer, a copying machine, or a facsimile, and further, it is also used in an industrial system such as a printing device.
On the other hand, in a conventional bubble jet recording method, the heating is repeated in the state where the heating element is in contact with ink, and therefore, there have been some cases where deposits caused by the scorching of ink is produced on the surface of the heating element. Furthermore, in the case where the liquid to be discharged is a liquid which may easily be degraded by heat, or in the case where the liquid to be discharged is a liquid in which it is difficult to sufficiently obtain the bubbling, there are some cases where a preferable discharge cannot be performed by the direct heating bubble formation using the above heating element.
In contrast with this, the applicant of the present application has proposed a method in which the bubbling liquid is bubbled by thermal energy to discharge the discharge liquid, through a flexible film separating the bubbling liquid and the discharge liquid in Japanese Patent Application Laid-Open No. 55-81172. The configuration of the flexible film and the bubbling liquid in this method is a constitution in which the flexible film is provided at a part of a nozzle, but in contrast with that, a constitution using a large film for separating the total of a head into an upper part and a lower part is disclosed in Japanese Patent Application Laid-Open No. 59-26270. This large film is provided with a purpose of preventing the liquids in 2 liquid flow passages from being mutually mixed, by being held between 2 sheet members forming the liquid flow passage.
On the other hand, as a constitution in which the bubbling liquid itself has characteristics and bubbling characteristics are considered, there is a constitution which is disclosed in Japanese Patent Application Laid-Open No. 5-229122 and uses a liquid with a boiling point lower than that of the discharge liquid, or a constitution which is disclosed in Japanese Patent Application Laid-Open No. 4-329148 and uses a conductive liquid as bubbling liquid.
However, when the present inventor and others examined to actually manufacture a liquid discharge head using such a separation film, the following problems were found.
That is, since the separation film is positioned between a base board having a plurality of heating elements and a top board for forming a common liquid chamber, there is an anxiety that a mounting device of the film is complicated or that the film is damaged when mounting the film, in the case of independently handling a deformable separation film.
Furthermore, it is difficult to adhere the film at desired positions of the ink flow passage provided in a head and the heater, and to surely fix the area other than the movable portion of the film, and it is considered that the dispersion in discharge performance depending on products may increase. Furthermore, since the liquid discharge caused by the bubble formation by the thermal energy is performed through the displacement of the separation film, there is an anxiety that the discharge efficiency may be lowered at that rate. Accordingly, in case of using the structure of a film applied for a patent by the present inventor and others for attaining a liquid discharge with a higher level while keeping the effect created by the separating function of a separation film, it is necessary to solve this problem by a simple method.
Furthermore, from another view point, the present inventor and others have found a new technological problem which has not existed previously, in the case of performing a liquid discharge based on the bubble formation caused by film boiling using an organic film and using a heating element. That is, it is a technological problem found by considering the thermal factor in the displacement of a separation film accompanied with a series of changes of generation of bubblesxe2x80x94growthxe2x80x94deforming, or by considering the practically probable situation of improving the durability for a separation film simple substance or an ink jet head.
It is a first object of the present invention to provide a liquid discharge head which solves the above problems, and which has a small dispersion in discharge performance depending on products and has a high reliability, and which can record a highly detailed image.
It is a second object of the present invention to provide a liquid discharge head which solves the above problems, and which further improves the discharge efficiency of liquid by a simple constitution while keeping the effect based on the separating function of a separation film.
It is a third object of the present invention to provide a manufacturing method of a liquid discharge head which solves the above problems, and which has a small dispersion in discharge performance depending on products and has a high reliability.
It is a fourth object of the present invention to provide a manufacturing method of a liquid discharge head in which a damage of a movable film in the manufacturing step or the like is prevented by eliminating the step of independently handling a movable film.
It is a residual object of the present invention to provide various related inventions to be described later of a manufacturing method of a liquid discharge head, a liquid discharge head, a head cartridge, a liquid discharge device or the like which have been created by the present inventor and others in the course of solving the above problems.
A liquid discharge head of the present invention for solving the above problems is a liquid discharge head comprising: a plurality of first liquid flow passages which are connected to outlets for discharging discharge liquid; a plurality of second liquid flow passages which have an element board with heating elements for generating bubbles in bubbling liquid and which correspond to the above first liquid flow passages; and movable separation films which substantially and mutually separate the above first liquid flow passages and the above second liquid flow passages corresponding thereto at all times, wherein the above movable separation films are mutually independent individual separation films for the above respective second liquid flow passages.
According to the above liquid discharge head, it is possible to directly provide a flow passage wall configuring a side wall of a first liquid flow passage on the element board by the low temperature (normal temperature) junction by using surface activation since the movable separation films are individual separation films. Consequently, the junction of the flow passage wall to the element board is surely performed and the dispersion in discharge characteristics depending on the lot of products or the like can be restrained as a result.
Furthermore, a liquid discharge head of the present invention is a liquid discharge head comprising: a first liquid flow passage connected to an outlet for discharging discharge liquid; a second liquid flow passage which has an element board with a heating element for generating bubbles in bubbling liquid and which corresponds to the above first liquid flow passage; and a movable separation film which substantially and mutually separates the above first liquid flow passage and the above corresponding second liquid flow passage at all times, wherein the liquid discharge head further comprises a seat to which the above movable separation film is physically or chemically joined, and the above movable separation film is not physically and chemically joined to the end portion on the above heating element side of the above seat.
According to the above liquid discharge head, since the movable separation film is joined to the seat but it is not joined to the end portion on the heating element side of this seat, it is possible to enlarge the movable area of the movable separation film. Consequently, the amount of displacement of the movable separation film based on the generation of bubbles in the second liquid flow passage is increased, and the discharge efficiency of the discharge liquid is improved.
Furthermore, a liquid discharge head of the present invention is a liquid discharge head comprising: a plurality of first liquid flow passages connected to outlets for discharging discharge liquid; a plurality of second liquid flow passages which have an element board with heating elements for generating bubbles in bubbling liquid and which correspond to the above first liquid flow passages; and a movable separation organic film which substantially and mutually separates the above first liquid flow passages and the above second liquid flow passages corresponding thereto at all times, further comprising a seat to which the above movable separation organic film is physically or chemically joined, wherein the tip portion of a flow passage wall provided for dividing the above plurality of first liquid flow passages is pressed toward the joining area of the above movable separation organic film joined to the above seat, and the width W1 of the above tip portion is smaller than the width W2 of the above joining area.
According to the above liquid discharge head, the position of the end portion of the contact area with the flow passage wall of the movable separation organic film is shifted from the position of the fixed end (end portion of the joining area to the seat) of the movable area of the movable separation organic film, and when the movable member is displaced to the first liquid flow passage side accompanied with the generation of bubbles, the force by the end portion of the flow passage wall is not applied to the movable separation organic film, and therefore, the durability of the movable separation organic film is improved.
Furthermore, a liquid discharge head of the present invention of another mode is a liquid discharge head comprising: a first liquid flow passage connected to an outlet for discharging discharge liquid; a second liquid flow passage which has an element board with a heating element for generating bubbles in bubbling liquid and which corresponds to the above first liquid flow passage; and a movable separation film which substantially and mutually separates the above first liquid flow passage and the above corresponding second liquid flow passage at all times, further comprising a seat to which the above movable separation film is joined, wherein the above movable separation film is adhered through an adhesive area patterned to the above seat.
According to the above liquid discharge head, since the movable separation film is adhered on the element board through an adhesive area patterned to the above seat, the adhesive force of the fixing portion of the movable separation film becomes strong. As a result of that, since it is possible to respectively surely make the fixed part and the movable part of the movable separation film function as a fixed portion and a movable portion, the action of the movable separation film becomes stable, and as a result, a stable discharge characteristic can be obtained. Furthermore, since the adhesive area is formed by being patterned to the seat, the leak of adhesives to the unnecessary part is prevented and the movable range of the movable member is highly accurately ensured, and the discharge characteristics are stabilized. Furthermore, by using a silane coupling agent as an adhesive, the durability of the adhered part is improved.
A manufacturing method of a liquid discharge head of the present invention is a manufacturing method of a liquid discharge head which comprises: a first liquid flow passage connected to an outlet for discharging liquid; a second liquid flow passage having a heating element for generating bubbles in liquid; and a movable separation film substantially and mutually separating the above first liquid flow passage and the above second liquid flow passage at all times, comprising the steps of: forming a seat for supporting the above movable separation film with a clearance to the above heating element, on an element board where the above heating element is formed; forming a sacrificial layer at least at a position to be the above clearance of the above element board; forming the above movable separation film on the above seat covering the above sacrificial layer; performing etching from the rear of the above element board and forming a through hole in the above element board letting the above sacrificial layer be an etching stop layer; and eliminating the above sacrificial layer through the above through hole and forming the above second liquid flow passage.
According to the above manufacturing method of a liquid discharge head, since the movable separation film can be provided integrally on the element board, it does not occur to independently handle an extremely thin movable separation film in the manufacturing step, and the risk of damage of the movable separation film is eliminated. Accordingly, a liquid discharge head is manufactured, which has a small dispersion in discharge characteristics caused by the damage of the movable separation film and has a high reliability.
A manufacturing method of a liquid discharge head of the present invention of another mode is a manufacturing method of a liquid discharge head which comprises: a first liquid flow passage connected to an outlet for discharging liquid; a second liquid flow passage having a heating element for generating bubbles in liquid; and a movable separation film substantially and mutually separating the above first liquid flow passage and the above second liquid flow passage at all times, comprising the steps of: forming a sacrificial layer at a position to be the above second liquid flow passage on an element board where the above heating element is formed; forming adhesives covering the above sacrificial layer on the top of the above element board where the above sacrificial layer is formed; forming the above movable separation film on the top of the above adhesives; performing etching from the rear of the above element board and forming a through hole in the above element board letting the above sacrificial layer be an etching stop layer; eliminating the above sacrificial layer through the above through hole; and eliminating the above adhesives exposed by elimination of the above sacrificial layer, through the above through hole and forming the above second liquid flow passage.
According to the above manufacturing method of a liquid discharge head, the adhesives for adhering the movable separation film on the element board are accurately patterned while leaving only the fixed part of the movable separation film. Accordingly, a liquid discharge head is manufactured, in which the leak of adhesives or the failure of adhesion does not occur and the movable range of the movable separation film is highly accurately ensured and the dispersion in discharge characteristics is small. Furthermore, since the movable separation film is integrally provided on the element board, it does not occur to independently handle the movable separation film, the risk of damage the movable separation film is eliminated. As a result of that, a liquid discharge head which has a small dispersion in discharge characteristics caused by the damage of the movable separation film and has a high reliability is manufactured.
Furthermore, the present invention provides a head cartridge having the above liquid discharge head, and a liquid discharge device.
Moreover, as mentioned above, the present invention includes an invention based on the recognition of new problems created in the case of using an organic film as a material of the above separation film, and this invention will be understood by an example to be described later.
By the way, xe2x80x9cup streamxe2x80x9d and xe2x80x9cdown streamxe2x80x9d used in the description of the present invention are used as the expression related to the flowing direction of the liquid going to the outlet through the bubble generating area (or the movable member) from the supply source of the liquid, or related to the direction in this configuration.